[CentOS] Where are my /tmp and /var/tmp files?

Tue Aug 28 16:12:05 UTC 2018
Kenneth Porter <shiva at sewingwitch.com>

I was pulling my hair out this morning trying to figure out why my PHP web 
script could see files in /var/tmp/scriptname but I couldn't see them with 
ls or my text editor. I was certain I'd gotten rootkitted. Then I thought 
maybe it was a new chroot in the latest Apache config. It turns out it's 
systemd's unit file for Apache, which containerizes /tmp and /var/tmp for 
selected apps. The httpd.service unit file includes the PrivateTmp setting.

Here's some details for anyone else confused by this: